title: Transcranial doppler ultrasound blood flow velocity and pulsatility index as systemic indicators for Alzheimer's disease.
abstract: BACKGROUND
  Multiple lines of evidence suggest that cardiovascular co-morbidities hasten the onset of Alzheimer's disease (AD) or accelerate its course.
  
  
  METHODS
  To evaluate the utility of cerebral vascular physical function and/or condition parameters as potential systemic indicators of AD, transcranial Doppler (TCD) ultrasound was used to assess cerebral blood flow and vascular resistance of the 16 arterial segments comprising the circle of Willis and its major tributaries.
  
  
  RESULTS
  Our study showed that decreased arterial mean flow velocity and increased pulsatility index are associated with a clinical diagnosis of presumptive AD. Cerebral blood flow impairment shown by these parameters reflects the global hemodynamic and structural consequences of a multifaceted disease process yielding diffuse congestive microvascular pathology, increased arterial rigidity, and decreased arterial compliance, combined with putative age-associated cardiovascular output declines.
  
  
  CONCLUSIONS
  TCD evaluation offers direct physical confirmation of brain perfusion impairment and might ultimately provide a convenient and a noninvasive means to assess the efficacy of medical interventions on cerebral blood flow or reveal incipient AD. In the near term, TCD-based direct assessments of brain perfusion might offer the prospect of preventing or mitigating AD simply by revealing patients who would benefit from interventions to improve circulatory system function.
authors.affiliation: The Longtine Center for Neurodegenerative Biochemistry, Banner Sun Health Research Institute, Sun City, AZ, USA. alex.roher@bannerhealth.com
authors.forename: Alex E
authors.initials: AE
authors.lastname: Roher
authors.forename: Zsolt
authors.initials: Z
authors.lastname: Garami
authors.forename: Suzanne L
authors.initials: SL
authors.lastname: Tyas
authors.forename: Chera L
authors.initials: CL
authors.lastname: Maarouf
authors.forename: Tyler A
authors.initials: TA
authors.lastname: Kokjohn
authors.forename: Marek
authors.initials: M
authors.lastname: Belohlavek
authors.forename: Linda J
authors.initials: LJ
authors.lastname: Vedders
authors.forename: Donald
authors.initials: D
authors.lastname: Connor
authors.forename: Marwan N
authors.initials: MN
authors.lastname: Sabbagh
authors.forename: Thomas G
authors.initials: TG
authors.lastname: Beach
authors.forename: Mark R
authors.initials: MR
authors.lastname: Emmerling
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D001783:Blood Flow Velocity / Q000502:physiology; D002560:Cerebrovascular Circulation / Q000502:physiology*; D002941:Circle of Willis / Q000000981:diagnostic imaging / Q000473:pathology; D005260:Female; D006801:Humans; D008297:Male; D008609:Mental Status Schedule; D008875:Middle Aged; D012372:ROC Curve; D017585:Ultrasonography, Doppler, Transcranial